LEON-G100 / LEON-G200 - System Integration Manual
GSM.G1-HW-09002-G3
Preliminary
System description
Page 41 of 125
The recommendations of the antenna producer for correct installation and deployment (PCB
layout and matching circuitry) must be followed.
If an external antenna is used, the PCB-to-RF-cable transition must be implemented using either a suitable 50
Ω
connector, or an RF-signal solder pad (including GND) that is optimized for 50
Ω
characteristic impedance.
If antenna supervisor functionality is required, the antenna should have built in DC diagnostic resistor to ground
to get proper antenna detection functionality (See section 2.4.3 Antenna detection functionality).
1.8
SIM interface
An SIM card interface is provided on the board-to-board pins of the module. High-speed SIM/ME interface is
implemented as well as automatic detection of the required SIM supporting voltage.
Both 1.8 V and 3 V SIM types are supported: activation and deactivation with automatic voltage switch from 1.8
to 3 V is implemented, according to ISO-IEC 78-16-e specifications. The SIM driver supports the PPS (Protocol
and Parameter Selection) procedure for baud-rate selection, according to the values determined by the SIM
Card.
Table 14 describes the pins related to the SIM interface:
Name
Description
Remarks
VSIM
SIM supply
1.80 V typical or 2.85 V typical automatically generated by the
module
SIM_CLK
SIM clock
3.25 MHz clock frequency
SIM_IO
SIM data
Internal 4.7 k
Ω
pull-up to
VSIM
SIM_RST
SIM reset
Table 14: SIM Interface pins
A low capacitance (i.e. less than 10 pF) ESD protection device (e.g. Infineon ESD8V0L2B-03L or AVX
USB0002RP or AVX USB0002DP) must be placed near the SIM card holder on each line (
VSIM
,
SIM_IO
,
SIM_CLK
,
SIM_RST
). SIM interface pins ESD sensitivity rating is 1 kV (HBM JESD22-A114F): higher
protection level is required if the lines are connected to a SIM card holder/connector, so they are
externally accessible on the application board.
For more details about the general precautions for ESD immunity about SIM pins, refer to chapter 2.5.1.
Figure 24 shows the minimal circuit connecting the LEON and the SIM card. This shows the
VSIM
supply
connected to the VPP pin (contact C6) of the SIM card as well as VCC (contact C1). Providing VPP was a
requirement for 5 V cards, but under
3GPP TS 51.011 specification
[16], 3 V and 1.8 V SIM cards do not require
VPP and the mobile equipment (ME) need not provide contact C6. If the ME provides contact C6, then it can
either provide the same voltage as on VCC or it can leave the signal open, but it cannot connect VPP to GND.